abc's dan harris now on crimes solved by little clues. and he's asking, if you saw them, what would you do? >> reporter: this modest house at 2207 seymour avenue -- were there missing clues here? and if you had seen them, what would you have done? >> for ten years, right under your nose. wow, it's heartbreaking, actually. >> reporter: vigilance from everyday citizens has made all the difference in some major cases. people living near this small house in texas reported seeing the image of a young girl gliding past a window. child protective services found 9-year-old victoria kept hidden and in squalor by her own mother. then there was what an 11-year-old boy named matthew dixon saw in the woods in oregon. another young boy walking with a man matthew found suspicious. >> well, when he said he was hunting and he didn't have a gun with him. it just seemed odd. >> reporter: he later told his mom to call the cops, which led police to take out the kidnapper and rescue young tanner kahn. and of course there was the campus police officer at the un